Blender scripting: Subdivided vertices with Catmull-Clark
It seems this question already answers how to apply a modifier; if you still get the parameters of a modifier, here's how:

import bpy

for ob in bpy.context.selected_objects:
    for mod in ob.modifiers: 
        if mod.type == 'SUBSURF':
           print("Subsurface modifier (\"%s\") in object \"%s\", with view level %s and render level %s." % (ob.name, mod.levels, mod.render_levels))
           bpy.ops.object.modifier_apply(apply_as='DATA', modifier=mod.name)


The above script will print to the console the level of all Subsurface modifiers in all selected objects, and their names.
Then it will apply the modifiers, so that you can get the coordinates of each vertex.